cmd/link: linker memory use increase from 1.10 to 1.11 #26186
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The sym.Symbol 'Reachparent' field is used only when field tracking is enabled. So as to use less memory for the common case where field tracking is not enabled, remove this field and use a side table stored in the context to achieve the same functionality. Updates #26186 Change-Id: Idc5f8b0aa323689d4d51dddb5d1b0341a37bb7d2 Reviewed-on: https://go-review.googlesource.com/121915 Reviewed-by: Ian Lance Taylor <iant@golang.org>
The linker's sym.Symbol struct contains two string fields, "Dynimplib" and "Dynimpvers" that are used only in very specific circumstances (for many symbols, such as DWARF syms, they are wasted space). Split these two off into a separate struct, then point to an instance of that struct when needed. This reduces the size of sym.Symbol so as to save space in the common case. Updates #26186 Change-Id: Id9c74824e78423a215c8cbc105b72665525a1eff Reviewed-on: https://go-review.googlesource.com/121916 Reviewed-by: Ian Lance Taylor <iant@golang.org>
The sym.Symbol 'Reachparent' field is used only when field tracking is enabled. So as to use less memory for the common case where field tracking is not enabled, remove this field and use a side table stored in the context to achieve the same functionality. Updates #26186 Change-Id: Idc5f8b0aa323689d4d51dddb5d1b0341a37bb7d2 Reviewed-on: https://go-review.googlesource.com/121915 Reviewed-by: Ian Lance Taylor <iant@golang.org>
The linker's sym.Symbol struct contains two string fields, "Dynimplib" and "Dynimpvers" that are used only in very specific circumstances (for many symbols, such as DWARF syms, they are wasted space). Split these two off into a separate struct, then point to an instance of that struct when needed. This reduces the size of sym.Symbol so as to save space in the common case. Updates #26186 Change-Id: Id9c74824e78423a215c8cbc105b72665525a1eff Reviewed-on: https://go-review.googlesource.com/121916 Reviewed-by: Ian Lance Taylor <iant@golang.org>
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Change https://golang.org/cl/122475 mentions this issue: |
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Change https://golang.org/cl/122482 mentions this issue: |
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Change https://golang.org/cl/121198 mentions this issue: |
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Should we move this issue's milestone to 1.12 at this point? |
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Change https://golang.org/cl/123296 mentions this issue: |
I suppose that make sense. Done. |
The linker's DWARF generation occasionally computes and attaches an attribute X to a type even though the type's abbrev doesn't have the specified attr. For example, the DW_TAG_subroutine_type abbrev entry has no type attribute, but a type attr is given to it (wasting memory). Similarly there are some places where a byte size attr is added to a DIE whose abbrev lacks that attr. This patch trims away a few of these not-needed attrs, saving some very tiny amount of memory. Updates #26186 Change-Id: I69e853df468ac54b07772a614b4106d7c4dae01d Reviewed-on: https://go-review.googlesource.com/123296 Reviewed-by: Heschi Kreinick <heschi@google.com> Run-TryBot: Heschi Kreinick <heschi@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org>
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Change https://golang.org/cl/125476 mentions this issue: |
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Change https://golang.org/cl/125477 mentions this issue: |
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Change https://golang.org/cl/125478 mentions this issue: |
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Change https://golang.org/cl/125479 mentions this issue: |
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I ran into this issue. Not able to build go 1.11 on raspberry pi with 433 MB of RAM: #26523 , go 1.10 builds fine |
Create a new "AuxSymbol" struct into which 'cold' or 'infrequently set' symbol fields are located. Move the Extname field from the main Symbol struct to AuxSymbol. Updates #26186 Change-Id: I9e795fb0cc48f978e2818475fa073ed9f2db202d Reviewed-on: https://go-review.googlesource.com/125476 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
The sym.Symbol 'Localentry' field is used only with cgo and/or external linking on MachoPPC. Relocate it to sym.AuxSymbol since it is infrequently used, so as to shrink the main Symbol struct. Updates #26186 Change-Id: I5872aa3f059270c2a091016d235a1a732695e411 Reviewed-on: https://go-review.googlesource.com/125477 Reviewed-by: Ian Lance Taylor <iant@golang.org>
The sym.Symbol 'Plt' and 'Got' field are used only with cgo and/or external linking and are not needed for most symbols. Relocate them to sym.AuxSymbol so as to shrink the main Symbol struct. Updates #26186 Change-Id: I170d628a760be300a0c1f738f0998970e91ce3d6 Reviewed-on: https://go-review.googlesource.com/125478 Reviewed-by: Ian Lance Taylor <iant@golang.org>
The sym.Symbol 'ElfType' field is used only for symbols corresponding to things in imported shared libraries, hence is not needed in the common case. Relocate it to sym.AuxSymbol so as to shrink the main Symbol struct. Updates #26186 Change-Id: I803efc561c31a0ca1d93eca434fda1c862a7b2c5 Reviewed-on: https://go-review.googlesource.com/125479 Reviewed-by: Ian Lance Taylor <iant@golang.org>
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I think we've hit the same wall. I can't make our CircleCI build to pass with Go 1.11.1 due to link failures Edit: I found a workaround by using |
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In the CircleCI case in particular, through https://groups.google.com/forum/?pli=1#!topic/golang-nuts/E9viXwCsHJA with @ianlancetaylor's help I found out that when running on Docker in Circle, Go thinks there are 36 CPUs, which means the default number of parallel build processes will be 36, so it's not very surprising to run into OOM errors. According to https://circleci.com/docs/2.0/configuration-reference/#resource_class, the default Docker container only has 2 CPUs available. So |
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@thanm Looks like most of the CLs attached to this issue have been submitted. Is there anything more to do here? |
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Yes, I think we should close it out. Austin has been collecting a list of more heavyweight things to do to improve linker performance (time and space) for post 1.12 development. |
What version of Go are you using (
go version)?tip:
go version devel +1e1bd239c5 Thu Jun 28 16:10:19 2018 -0400 linux/amd64
Does this issue reproduce with the latest release?
Yes
What operating system and processor architecture are you using (
go env)?GOARCH="amd64"
GOHOSTARCH="amd64"
GOHOSTOS="linux"
What did you do?
When I build large Go programs, I note that memory consumption has increased during the link step, when moving from Go 1.10 to Go 1.11; it seems that the linker is taking more memory than it used to. The memory consumption increase varies from program to program, but looks on the order of 20-30%. Building "hyperkube" from kubernetes tip (1.11) is one example. The 20% number is is derived from building a specific copy of "hyperkube" with 1.10 & 1.11 and comparing heap profiles collected via
go build -ldflags "-memprofile XXX -memprofilerate 1"
using "go tool pprof". Link steps that use the external linker (for CGO) have larger increases.
The current theory is that this is related to additional DWARF symbols/sections/relocations that the compiler is emitting (for example, DWARF location lists are now enabled with 1.11, as are DWARF inline info records).
It would be worth doing some work to figure out exactly where the memory increase is coming from, and submitting fixes to bring down the overall usage if possible, so as to avoid having the linker run out of memory when linking very large Go programs.
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